Due to low working voltage, low power consumption, flexible display modes, low radiation, and so on, a liquid crystal display (LCD) has been widely applied in various fields, such as the fields of computer, mobile phone, television, and measurement display. An LCD includes an LCD panel, which includes a thin-film transistor substrate, a color filter substrate and a liquid crystal molecule layer sandwiched between the two substrates. Besides, the LCD also includes a backlight module for supplying a light source to the LCD panel, so that the LCD can display images.
As shown in FIG. 1, a traditional backlight module includes a back cover 10, a bezel 20, a mold frame 30, an optical sheet 40, a light guide plate (LGP) 50, an LED lamp strip and others. As the frame of a display product becomes slimmer and slimmer, the bezel of a backlight module is required to be slimmer and slimmer, too. In the traditional backlight module, the optical sheet is positioned in the following two ways.
The first way is, as shown in FIG. 1, to process a bending structure on the back cover 10 between the mold frame 30 and the LGP 50 to form a sheet guide 10a, and to design a positioning hole 40a at an edge of the optical sheet 40 and the positioning hole 40a corresponding to the sheet guide 10a, thus facilitating the positioning assembly of the optical sheet 40 and the back cover 10 and having an effect on fixing of the optical sheet 40; however, in this structure, due to the bending structure processed on the back cover 10, it can be difficult to make the bezel of the backlight module slimmed, which causes difficulties in making the frame of the display product slimmed, too.
The second way is, to process a separated circular positioning column on the back cover, and to design a U shaped positioning recess capable of coordinating with the circular positioning column; the bezel in this structure can be slimmed to some extent relative to the bending structure of the back cover in the first way; but, it needs to reserve a certain space for producing the positioning column on the back cover, that is, the positioning column still takes up some space on the bezel, and the cost for producing the separated circular positioning column on the back cover is high, moreover, poor movement of the optical sheet often occurs in the coordination of the circular positioning column and the U shaped positioning recess.